Can we add a preview of email contents when mousing over subject, like in Batchbook CRM?

Can we add a preview of email contents when mousing over subject, like in Batchbook CRM?

Batchbook does this wonderfully, it's so useful.  When you hover your mouse over the email subject on a contact's page (or recent activity dashboard), a box pops up showing the first 9 or so lines of the email.  This way you can easily hover over several email subjects in succession to find what you are looking for, instead of clicking on each one.